The first concerning incident happened on January 29. It started with four people on board. They made it out safely, but that bus was left a smoldering shell.
"That shouldn't happen. Not on a bus," said Yvonne, a Bellaire High School grandparent.
READ MORE: HISD bus carrying student with special needs catches fire
The next day, an ABC13 viewer sent in a video of a bus smoking so badly on the 610 Loop, he said it stopped traffic. No injuries were reported in that incident either.
That made ABC13 ask HISD, how often are these bus fire or smoking incidents happening?
Documents show there were 78 reports in 2018 and 67 in 2019. HISD said there have been about five so far this year. But with the two ABC13 covered over the past few weeks, that's a total of seven for 2020.
A total of 152 incidents in just over two years.
READ MORE: Smoke and fire: 2 scary HISD bus incidents in 2 days
ABC13 anchor Steven Romo spoke with a woman who said she worked as an HISD bus driver for about two years. She wished to remain anonymous and said she left the job over stress about bus problems.
"What changed your mind about school buses once you started driving them?" Romo asked.
"Once I was on the inside and saw what really happened and how they really don't maintain those buses like they should, it was concerning for me," she said.
HISD sent maintenance information for its fleet, saying the buses are inspected annually for state regulations, and the bus drivers walk through the fleet on a daily basis looking for problems.
"Most of the fleets I know running school buses, they have a semi-annual inspection, maybe twice a year, maybe four times a year," said Doug Walter, a specialist in fleet vehicles for Kacal Automotive.
His shop doesn't work for HISD, but services many other buses. He said drivers and mechanics want to get it right because they use these streets, too.
"I don't want to be driving next to a school bus [that] a part is going to fall off of," Walter said.
Problems start when buses begin to age.
HISD said in a statement half its fleet is more than 12 years old, and a third of them are 15 years or older. Walter points out even though bus smoking and fire incidents are alarming, injuries from them are pretty rare.
"Fires are more common in actual passenger cars," he said. "Kids are safer inside a bus than they are walking."
Despite that information, not everyone is reassured.
"I know from my experience, personally, I would not let my kids ride the bus," said the former HISD bus driver.
Below is a response from HISD Transportation Services:
"In HISD, the safety of our students and employees is always our top priority. Any time an issue is reported, the bus in question is immediately inspected and pulled out of service for repairs, if needed. That said, it's not uncommon to experience occasional mechanical issues with aging school buses, as with any aging vehicle. HISD has a fleet of 1,113 school buses, almost half of which are over 12 years old and almost one-third of which are more than 15 years old.
Additionally, some HISD buses are equipped with self-cleaning exhaust regeneration systems, which occasionally generate smoke from the exhaust pipe as part of their diesel filter cleaning process. Of the 109 buses on the list, 78 of them have this system in place."
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